This invention relates generally to electrical connectors. More specifically, the invention relates to electrical connectors which are configured to mate with shunted electrical terminals, and which include a shunt displacement member for selectably deshunting the terminals.
Electrical terminals associated with circuits for activating explosive devices such as airbag detonators, pyrotechnic actuators and the like often include a shunting member for preventing inadvertent activation of the circuit. The shunting member is disposed so as to establish electrical contact between selected portions of the circuit thereby deactivating the circuit and preventing activation of the explosive device. In most instances, shunted terminals are configured so that a fixed projection in a mating connector displaces the shunt member at the time final connection of the circuitry is made.
Automobiles and other motor vehicles typically include a number of detonators for activating airbags and tensioning seat belts in the event of a crash. These explosive devices can present a hazard during the assembly and testing of motor vehicles should they be inadvertently deployed. Consequently, it is standard practice in the industry to include one or more shunting members in the activation circuitry for such devices. These shunts are disposed so as to short out or ground the activation circuitry and prevent inadvertent detonation as a result of accumulated static electricity, improper connection or the like.
In the course of assembling motor vehicles, it is necessary to test the airbag and seat belt tensioning circuitry to verify that it has been properly installed and is functional. Such testing requires displacement of the shunting members. Furthermore, testing generally requires that circuits are tested both with the shunts in place and with various of the shunts removed. Previously, testing of terminals in a shunted and unshunted condition required a testing protocol in which two separate connections were sequentially made to the shunted terminal. In this approach, a first connection would be made with a connector not having a shunt displacement member, so as to allow data collection from the shunted circuit. A second connection would then be made employing another connector having a shunt displacement member, and data would be collected on the unshunted circuitry. This approach required sequential connections to be made and broken thereby requiring significant labor and introducing numerous sources of error. In addition, this approach is very impractical in the situation where activation circuitry may include a number of separately shunted terminals which must be tested under conditions wherein different combinations of shunted and unshunted terminals are required.
One approach to simplifying the testing of shunted terminals is shown in U.S. Pat. No. 6,155,855. This patent discloses a test connector for use in conjunction with shunted terminals. The connector is configured to engage a shunted terminal in one of two positions. In a first position wherein the connector is only partially seated with the terminal, electrical communication with the terminal is established, but the shunt member is not displaced. The connector of the ""855 patent may then be moved to a fully seated position wherein a shunt displacement member engages and displaces the shunt thereby permitting measurements to be made on the unshunted circuit. While this device overcomes some of the problems of the prior art, it still requires two separate mechanical manipulations of the connector and terminal. In addition, electrical connection in the partially engaged state can be erratic. Furthermore, connectors of this type do not allow for rapid, selectable shunt member displacement, and are not advantageous for use in situations where a plurality of measurements are being made on a number of combinations of shunted terminals.
Accordingly, there is a need for a connector which can establish electrical communication with a shunted terminal assembly, and which is capable of automatically displacing the shunting member. The connector should be capable of providing for the displacement and replacement of the shunting member, without requiring the connection to the terminal assembly to be interrupted. Most preferably, the shunting and deshunting action should be controllable by an electronic or fluidic circuit. As will be explained in detail hereinbelow, the present invention provides a connector which meets these criteria. The connector of the present invention is simple to operate, rapid in action, and capable of repeatedly displacing and replacing a shunting member. As such, the connector of the present invention is readily adaptable to a variety of test equipment and procedures. These and other advantages of the invention will be apparent from the drawings, discussion and description which follow.
Disclosed herein is a connector for establishing electrical communication with a shunted electrical terminal of the type comprising a terminal housing having supported therein an electrically conductive terminal member and an electrically conductive shunt member. The shunt member is movable from a first, shunting, position in which it is in electrical communication with the terminal member to a second, unshunted, position where it is not in electrical communication with the terminal member. The connector of the present invention includes a connector housing which is configured to mechanically engage the terminal housing. The connector further includes an electrically conductive contact member supported by the connector housing. The contact member is disposed and configured to engage, and establish electrical contact with, the terminal member when the connector housing is in mechanical engagement with the terminal housing. The contact member also includes a shunt displacement member which is supported by the connector housing. The shunt displacement member is selectively activatable when the connector housing is in mechanical engagement with the terminal housing, to move the shunt member from the shunting position to the unshunted position.
In specific embodiments of the present invention, the displacement member is electrically activatable to move the shunt member, and in such instances may include a solenoid or linear actuator. In other embodiments, the displacement member may be fluidically activatable, as for example by a pneumatic or hydraulic system.
The connector of the present invention is particularly suited for use in connection with a test circuit, such as a test circuit for testing a pyrotechnical actuator. The present invention also includes a method for testing a shunted terminal, which method employs the connector of the present invention.